package org.yaac.server.egql.evaluator.function;

import java.math.BigDecimal;

import org.yaac.server.egql.evaluator.EvaluationResult;
import org.yaac.server.egql.exception.EGQLException;
import org.yaac.server.egql.processor.ProcessData.ProcessDataRecord;
import org.yaac.shared.ErrorCode;

/**
 * @author Max Zhu (thebbsky@gmail.com)
 *
 */
public class RoundFunction extends Function {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	@Override
	public void validate() throws EGQLException {
		FunctionUtil.ensureParamSize(ops, 2);
	}

	@Override
	public EvaluationResult evaluate(ProcessDataRecord record) {
		if (this.ops.isEmpty()) {
			return new EvaluationResult(null).withWarning(ErrorCode.W114);
		} else if (this.ops.size() == 2) {
			EvaluationResult r = ops.get(0).evaluate(record);
			EvaluationResult scale = ops.get(1).evaluate(record);
			if (r.getPayload() instanceof Number && scale.getPayload() instanceof Number) {
				BigDecimal bd = (BigDecimal) r.getPayload();
				BigDecimal scaleBd = (BigDecimal) scale.getPayload();
				return new EvaluationResult( 
						bd.setScale(scaleBd.intValue(), BigDecimal.ROUND_HALF_UP), r, scale);
			} else {
				return r.withWarning(ErrorCode.W113);
			}
		} else {
			return ops.get(0).evaluate(record).withWarning(ErrorCode.W114);
		}
	}

}
